There are many systems for covering top apertures of truck-movable containers, such as open top truck trailers and the bin of dump trucks. Many such systems conveniently roll a tarpaulin covering the top aperture around a rod when the top aperture is uncovered. To facilitate operation of these system, many are provided with an electric motor. However, if the motor fails, the system becomes inoperable.
Against this background, there exists a need for an improved tarpaulin extension and retraction device. An object of the present invention is to provide such a device.